This invention relates to a video memory usable in various systems such as graphics and character display systems.
In some display systems, video data representing graphics or character information are indicated on a CRT. Such a display system has a video memory for storing video data. In general, the video memory used in such a display system is of a dual-port type having a random port and a serial port. The random port is used to draw the video data while the serial port is used for the readout of data indicated on the CRT.
In prior art video memories of the dual-port type, the bit width of a data input/output terminal in the random port is considerably limited. Generally, the bit width of the data input/output terminal corresponds to 4 bits to 8 bits. The limited bit width tends to cause an insufficient speed of the data drawing.